SYNTHESIS AND MICROSTRUCTURAL CHARACTERIZATION OF LOW-MOLAR-MASS POLY(VINYLIDENE FLUORIDE)

The kinetic features of vinylidene fluoride (VDF) radical polymerizati on in solution, initiated by bis(4-t-butylcyclohexyl)peroxydicarbonate , have been investigated in three different solvents (acetone, ethyl a cetate and methyl acetate) under homogeneous conditions. Many signific ant deviations of the dependence of the polymerization rate on the 'id eal' 1.0 and 0.5 exponent values of monomer and initiator concentratio ns, respectively, are indicative of anomalous kinetic behaviours linke d to concurrent reactions, which are operative during such polymerizat ion. The complexity of the kinetic behaviour prevents, inter alia, the correct evaluation of chain transfer constants to the solvents from k inetic data. F-19 nuclear magnetic resonance spectroscopy has been use d in order to get full microstructural characterization of the low-mol ar-mass poly(vinylidene fluoride) (PVDF) synthesized under the above c onditions. Both chain transfer constants to the solvent and extent of chain inversions in PVDF have been evaluated by this technique.